Electric clock thermostat



May 19, 1936. A. G. McNlcoLL ELECTRIC CLOCK THERMOSTAT Filed Feb. 27, 1932 4 Sheets-Sheet l INVENTOR. ndz'ew -CjV/ca/Z, BY

l grn ATTORNEY` May 19, 1936. A.4 G. MoNlcoLL 2,041,363

ELECTRIC CLOCK THERMOSTAT Filed Feb. 27, 1952 4 sheets-sheet 2 160176 F c yy ,l "f fw 5% 33' "1'1'* +9 Q i?" Y l *f4 fl/05 fl 62 54 y C .2 O O O e l i4- a3 f5 10a 1 zo@ A zo?" 6P 10? 7 www# ` ATToRNEYf May 19, 1936. A. G. McNlcoLL 2,041,363

ELECTRIC CLOCK I THERMOSTAT Filed Feb. 2'?,l 1952 4 Sheets-Sheet 3 BY W# QV.

. ATTORNEYS May 1'9, 1936. A. G. McNlcoLL 2,041,363

I ELECTRIC CLOCK THERMOSTAT Filed Feb. 27, 1952 4 Sheets-s116191', 4

EL JZ f 115 .ff/lf3 17216.50 gzz INVENTOR.

ndrew GMNz'co/l,

ATTORNEYS Patented May 19, 1936 PATENT OFFICE ELECTRIC CLOCK THERMOSTAT Andrew G. MoNicoll, Minneapolis, Minn., as-

signor to Minneapolis-Honeywell Regulator Company, of Delaware Minneapolis, Minn., a corporation Application February 27, 1932, Serial No. 595,460

13 Claims.

The present application relates to clock thermostats and, while many of the features of the present invention are applicable generally to clock thermostats, and some of such features are applicable to simple thermostats without time control, the invention includes certain features which particularly adapt the disclosed organization for use in connection with an electricallydriven time-control unit.

Among the objects of the present invention is the production of an electric clock thermostat so constructed as to reduce to a minimum thel eiect of the heat generated by the clock motor upon the thermo-responsive element of the organization. A further object of the invention is to provide a device of the character indicated so constructed that the whole time-control unit may be readily removed from the organization or assembled therewith without the necessity of disconnecting or connecting any wires. A further object of the invention is to provide, in an organization of the character indicated, an electric timecontrol unit removably associable with the adjustable thermo-responsive mechanism of the organization in such a manner that the mere association of the control unit with the thermo-responsive mechanism automatically establishes the necessary electrical connections for driving the control unit; and that the said control unit may be removed from the organization without separate manipulation of the electrical control connections.

A further object of the invention is to provide, in a device of the character indicated, mechanism whereby, at pre-determined time intervals, .a constantly operating motor will be caused to shift an element of the thermostatic mechanism in one direction; and thereafter, after a predetermined interval, to shift said element in the opposite direction; such mechanism including improved and simplified clutching mechanism.

A further object of the invention is to provide, in a device of the character indicated, a simplified gear train and operating mechanism between a constantly operating motor, clock hands, certain other rotatable indicators, and a thermostatshifting mechanism.

A further object of the invention is to provide a simplified and improved manual adjustment for an element of the thermostatic mechanism.

Further objects of the invention will appear as the description proceeds.

To the accomplishment of the above and related objects, my invention may be embodied in the form illustrated in the accompanying drawings,

attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specic construction illustrated and described, so long as the scope of the appended claims is not violated.

Fig. l is a perspective view of an embodiment of the present invention;

Fig. 2 is a bottom plan thereof;

Fig. 3 is a front elevation thereof, the shield or cover having been removed, and certain of the indicia of the clock dial having been erased for clarity of illustration;

Fig. 4 is a side elevation of the mechanism illustrated in Fig. 3, the shield or cover being shown in substantially central vertical section;

Fig. 5 is a front elevation of the base of the mechanism illustrated in Fig. 3, broken fragments of the time-control unit being shown in association therewith;

Fig. 6 is a section, taken substantially on the line 6-6 of Fig. 5 and looking in the direction of the arrows, the time-control unit being shown partially assembled therewith;

Fig. 7 is a section taken substantially on the line 1 1 of Fig. 5, and looking in the direction of the arrows, the time-control unit having been removed;

Fig. 8 is a rear elevation of the base;

Fig. 9 is a section takensubstantially on the line 9 9 of Fig. 5, looking in the direction of the arrows;

Fig. 10 is a section through the time-control unit taken substantially on the line Ill-Ill of Fig. 11 and looking in the direction of the arrows, parts being broken away for clarity of illustration;

Fig. l1 is a side elevation of the time-control unit, certain parts being broken away for clarity of illustration;

Fig. 12 is a. rear elevation of the time-control unit, parts being broken away for clarity of illustration;

Fig. 13 is a fragmental view of certain of the parts illustrated in Fig. 12, such parts being shown in another position of operation;

Fig. 14 is a fragmental side elevation of a portion of the clutch actuating mechanism;

Fig. 15 is an enlarged plan of the mechanism illustrated in Fig. 14;

Fig. 16 is a section taken line lS-IS of Fig. l5; and

Fig. 17 is a front elevation of a detail.

Referring, rst, to Fig. 4, it will be seen that I have illustrated an electric clock thermostat comprising a metallic base indicated generally at 20,

substantially on the with which is associated a thermo-responsive element 2| of the well known volute type. In the particular embodiment illustrated, said element 2| includes a pair of spring fingers 22 and 23,' but it will be obvious that, without affecting the present invention, any other well known type of thermo-responsive contactor might be substituted for said element 2| with its fingers 22 and 23.

Said element 2| is supported upon a bracket 24 (Figs. 3, 5, and 7) which, in turn, is pivotally mounted upon a pin or bolt 25. Said bracket 24 is preferably provided with a bifurcated ear 26 between the furcations of which is received an eccentrically positioned pin 21 carried by an e1ement 28 rotatably mounted in a bridge piece 29 in which the pin 25 is likewise mounted. It will be obvious that rotation of the element 28 will result in bodily adjustment of the position of the thermo-responsive element 2|.

The bridge Ypiece 29 is preferably formed of heat-insulating material supported at some distance from the base 2|) by a pair of brackets 3| and 82, said bridge piece being secured to said brackets through the medium of screws 3U (see Fig. 3).

In its preferred embodiment, the base 20 comprises a metallic plate 33 provided with a perimetral flange 34 (Fig.` 7) forming, with said plate, a quasi-housing in which certain elements later to be described are received. Adjacent its upper end, the plate 33 is out away as at 35 to form a socket the base of which is formed by a block 36 of heat-insulating material. The bridge piece 29 and the block 36 are both preferably formed of some molded material having high insulating qualities with regard both to heat and to electricity.

Referring to Figs. 6 and 7, it will be seen that the block 36 is formedin opposite sides with a pair of parallel grooves or guideways 31, the forward edges of which are guarded by vertically extending ribs 38, and said guideways are open at their upper ends. Adjacent one of the guide ways 31 there are set into the block 36 a pair of contacts 39 and 40. The contact 39 is permanently connected by a wire 4| with a terminal 42, while a wire 43 permanently connects the contact 40 with a second terminal 44, said terminals 42 and 44 being set into a block 45 of insulating material received within the above-mentioned housing and secured in place by a bolt 46, or the like.

A time-control unit, indicated gene-rally at 41 in Fig. 11, comprises plates 48, 48', 49, and 58, suitably connected together by screws 5| and spaced from each other by spacer sleeves 52, said plates forming a frame upon which are hung the various elements of the time-control unit. A block 53 (Figs. 5 and ll) of insulating material is mounted upon the plate 48, and a pair of spring contacts 54 and 55 are set into the outer lateral surface of said block 53. Wires 56 and 51 respectively associated with said contacts 54 and 55 lead to the terminals of a constantspeed motor 58. The block 53 and the contacts 54 and 55 are so positioned that, when the timecontrol unit is slid home in its socket, the edges of the plate 48 being guided in the grooves 31, the contact 54 will engage the contact 39, and the contact will engage the Contact 4S. It will thus be seen that, if the terminals 42 and 44. are connected to a. source of electrical energy, the mere act of sliding the time-control unit into place will establish a suitable connection between the motor 58 and said source of energy; and

that the time-control unit may be removed for repair or replacement without disconnecting any wires or other manually manipulated connections.

It will also be seen that the present arrangement is such that there is no metallic path through which the heat generated by the operation of the motor 58 may flow to the thermoresponsive element 2| to affect the same. However, a device consisting merely of the elements illustrated in Fig. 3 would be entirely unsatisfactory, not only because its appearance would be objectionable, but because ofthe fact that delicate parts would be subjected to the possibility of damage from blows and to an excessive deposit of dirt. Consequently, it is essential to shield a device of this character in a suitable cover or housing. With a housing of the ordinary construction in place, the heat of the motor 58 would be somewhat confined, whereby the air within the housing would be raised, at times, to a temperature much too far above room temperature for satisfactory thermostat operation. Furthermore, with a housing of ordinary construction, the temperature variation between the interior of the housing and room temperature would fluctuate through a wide range depending upon conditions of circulation and other conditions. It is an object of the present invention to provide means whereby that temperature difference shall be held at as low a value as possible, and further shall be held as constant as possible.

A housing constructed in accordance with the present invention is indicated generally at 59 in Figs. 1 and 2. Said housing comprises a front panel 60 upon which is mounted a thermometer scale G! carrying a thermometer G2; is apertured adjacent its upper end to receive a crystal 63 through which the clock dial |45 is visible. Said housing includes likewise a perimetral flange 64 adapted to t over the base 29 and to enclose said base and all of the mechanism mounted thereon.

According to the present invention, the side Walls of the flange 64 are imperforate, as is also the front panel 60, except for an opening adjacent the lower end thereof. The upper wall 55 of said flange is formed with a plurality of apertures 66, and the lower wall 61 thereof is formed with a plurality of apertures 88. Because of the fact that the only openings in the housing 59 are at the upper and lower ends thereof, the heat generated by the motor 58 is put to work to assist in overcoming the disadvantages which arise because of the generation of that heat. The housing 59 acts, upon generatio-n of heat by the motor 58, as a chimney; whereby a draft is set up moving upwardly through the apertures 68, and over the thermostatic element 2|, and thence over the motor 58 and out through the apertures 66. Conduction of heat through the air from the motor 58 downwardly toward the thermostatic element 2| is thus positively prevented, and a stream of air is positively drawn from the room and caused to flow across the thermo-responsive element 2 Tests have shown that, as a result of this construction, the temperature of the air immediately adjacent the thermo-responsive element 2| is held with a considerable degree of constancy at a value very slightly above room temperature.

Referring, now, most particularly to Figs. 3, 5, 7, and 9, it will be seen that a plate B9 is mountf ed upon the plate 33, being pivoted thereto at its lower end upon a pin 18. Intermediate its ends,

and which said plate carries a post 1| and, spaced laterally from'said post 1|, a second post 12. The post 1| is suitably insulated by washers 14 from the plate 69, and carries a sleeve 13 through which is adjustably threaded a contact element 15. Said post also carries a second metallic sleeve 16 suitably insulated from said post and from said sleeve 13, by an insulating member 11. C The sleeve 16 carries an adjustable contact member 18. A bar v19 provides an electrical connection between the sleeve 15 and a sleeve 80 carried upon, and electrically connected to, said post 12, said post and sleeve being suitably insulated from the base 89 by washers 8|.A The contact element 15 is adapted to be contacted by the finger 22; and the contact element 18 is adaptedto be contacted by the iinger 23. A wire 82 (Fig. 8) permanently connects the post 1| with a terminal 83; and a wire 84 permanently connects the post 12 with a terminal 85, said terminals 83 and 85 being set in a block 86 of insulating material suitably secured by a bolt 81, or the like, -in the housing formed by the base 20. Said block 86 likewise carries a terminal 88 to which is permanently connected one end of a wire 89, the opposit'e end of which is connected to the pin 25, and thereby to the thermo-responsive element 2| and `the fingers 2'2 and 23. i

Slnce'the present invention relates to thermostats of the, type in which the position of the contact elements 15 and 18 is adapted to be automatically adjusted by a time-control unit, with respect to the thermo-responsive element, means must be provided for cooperation'with said timecontrol unit to effect such adjustment; and preferably, such means should be adjustable, to the end that the movement of the contact elements with respect to the thermo-responsive element, upon actuation by the time-control unit, shall be variable at the will ofthe user. Mechanism of such character has been provided in the device of the present application, and is illustrated most clearly in Fig. 5. A shoe 90 is carried upon one arm yoi? a lever 92, said lever being pivoted at 9| 'Y tothe plate 69. The opposite arm of said lever 92 carries an indicator 93 associated with 'a scale 94. "A second shoe 95 is positioned in opposition to the shoe 90 and is carried by one arm of .a lever 91 pivoted at 96 to the plate 89. 'I'he opposite arm of said lever 91 carries an indicator 98 associated with a second scale 99. It may here be noted that the levers 92 and 91 are tightly pivoted to the plate 89, so that they are movable about their pivots only with ditliculty; while the plate 69 is loosely pivoted to the plate 33, so that it is relatively easily movable about its pivot.

The time-control unit 41 includes a cam element or lever which, when the time-control unit is' seated in-the socket of the base, is positioned between the shoes 9.0 and 95, as is clearly illustrated in Fig. 5.

When said time-controlunit is so seated, an element |0| thereof is so positioned4as to be en-v gageable by the hook of -a latch arm |02 pivoted at |03 on the plate 33.

The scale 94 is marked Night; and the scale 99 is marked Day. If the indicator 93 is moved to a position wherein it points to a temperature which it is desired to maintain during those hours when the owner is-sleeping; and if the indicator 98 is set to a position to indicate on the scale 99 the temperature which it is desired to maintain during the waking hours of the owner, the time' control unit will automatically so position the plate'89 and consequently the contacts 15 and 18 that the temperatures indicated by the indicators 93 and 98 will be maintained during such periods, in the absence of manual adjustment of the plate 69 l carries an arm i I0 provided with a pin engage ing between the furcations |2 of a rearwardly projecting finger ||3 on the plate 89. Obviously, if the arm E01 is moved in one direction or the other, the arm l |0 will be correspondingly moved, and the pin lil will enforce corresponding movement of the plate 89 about its pivot 10, thereby adjusting the relation of the contacts and 18 to the fingers 22 and 23 of the -thermo-responsive element 2i.

The details of the trated in Figs. 1i The motor 50 is suitably mounted upon the plate Q8', and the spindle M4 of said motor carries a pinion ||5 meshing with a gear i I6. Said gear H6 is preferably formed of fiber in order to reduce the noise ofbperation, and is carried upon a shaft lill journalled between the plates 48 and 08'. Said shaft likewise carries a pinion ||8 meshing with a gear ii 9 i210. Likewise fast upon the shaft is a pinion 02| meshing witha'gear'l22 on a shaft |23. .At one end, said shaft |23 is journalled in the plate 138', and at its opposite end, said shaft is telescoped within a hollow shaft |24 journalled intermediate its ends in the plate 50. Said shaft |24 is formed with, or carries, a m element E25; and splined on said shaft i2 1s a clutch member B26 with which cooperates a yoke |21. Said yoke 021 is extended as a nger the extremity of which is loosely secured to the platel by a screw, or the like, ,|3|, the arrangement being such as to permit movement of said member |21 in a direction parallel to the axis of the shaft |24. A leaf time-control unit are illusspring A|32 urges said member |21, and consequently'said clutch memberkl, toward the cam element |25. Said member |21 is provided With a finger |28 projectingdn a direction parallel to.

the axis of the shai't E 24, and said spring |32 holds said finger |28 always in contact with said cam element |25.

to 17 inclusive, and in Fig. 3.

carried-upon a shaft n' Suitable gears of more or less conventional arrangement are provided whereby a shaft |33 is constantly driven from the motor '58. Said shaft |33 carries a pinion |34 meshing with a gear |35 loose on a shaft |38.

is compressed between the gear |35 and a pinion Y, E31 fast on the shaft |38 whereby said pinion |31 and shaft |38 are normally driven synchronously with the gear |35. Said pinion |31 meshes with .a gear |39 integral with a. pinion A spring washer |36 |42, said hands being h form of a disc divided into two equal segments,

one being light in color and the other being dark in color. The ratio of the pinion |46 to the gear |41 is such that the gear |41 is turned through one complete revolution in twenty-four hours, and a peep hole |48 is formed in the clock dial |45 through which a small portion of the disc |41 is constantly visible.

The clock hands are so related to, the disc |41 that, at twelve oclock noon and at twelve oclock midnight, the dividing line between the two segments of the disc |41 vertically bisects the hole A gear |49 mounted on a shaft |50 likewise meshes with the pinion |40, and said shaft |50 carries a second, gear |5| meshing with a gear |52 carried on a shaft |53, said shaft likewise carrying a dial |54. The ratio through the train |40|52 is such that the dial |54 is turned through one complete revolution in twenty-four hours. Said dial |54 is divided into two equal segments, and each segment is graduated and numbered from 1 to 12, as is clearly illustrated in Fig. 3. One-half of the dial |54 is light in color and the other half is dark in color; and

said dial is so related to the clock hands that,

at twelve oclock noon and at twelve oclock midnight, the dividing line between the two segments is positioned in registry with a lever arm |58, later to be described.

A knurled nut |55 is threaded on the shaft |53 and is adapted to be turned up to clamp in adjusted position two individually adjustable actuator fingers |56 and |51 clearly illustrated in Figs. 3 and 11. Said .fingers |56 and |51 are of conventional construction, and consequently are not herein described in detail.

One arm |58 of a trip lever is positioned for actuation by the fingers |56 and |51, said lever being pivoted at |59 in the plate 48. The opposite arm |60 of said levercarries a pivot pin IBI upon which is pivotally mounted a trigger |62 having an arm |63 (see Figs. 12 to 14) operatively associated with the cam element |25. A contractile spring |64 is suitably anchored at its one end and is connected to said trigger |62 at its opposite end, whereby the lever is urged to the position illustrated in Fig. 11, in which a lug |84 (Fig. 10) formed on said lever engages the plate 48 to limit movement of the lever under the influence of the spring |64.

Referring, now, to Fig. 16, it will be seen that the clutch member |26 is formed with a peripheral groove |65 in which the element |21engages. Said member |26 carries a pair of pins |66 the projecting ends of which are received in apertures |61 inthe cam element |25, whereby said clutch member and cam element are locked against relative rotation. In the position of Fig. 16, there is no driving' engagementl between -the shaft |28 and, the shaft |24.

The gear |22 may be considered a second clutch member with which the member |26 cooperates to effect a driving connection between the shaft |23 and the shaft |24.V When the lclutch member |26 is moved toward the left, as viewed in Fig. 16, under the inuence of the spring |32, the pins |66 are projected into the spaces |68 between the spokes |68 of the gear |22, whereby said gear and said clutch member |26 are locked against relative rotation.

The cam element |25 is formed with two diametrically opposite cam surfaces |10 and |1| gradually rising from the surface |14 of said cam element |25 to positions spaced from said surface a distance substantially equal to the disgear tance from the left-hand face of the gear |22 to the left-hand .face of the cam element |25, as viewed in Fig. 16. Said cam surface |10 terminates in a sharply dropping shoulder |12, and said cam surface |1| terminates similarly in a sharply dropping surface |13. The finger |28 of the element |21 is so positioned as to ride upon these cams so that when the cam element is in the position illustrated in Figs. 11, 12, 14, and 15, the spring |32 will be compressed, and the clutch element |26 will be held in such a position that the pins |66 are completely withdrawn from the gear |22.

Under these circumstances, of course, the shaft |24 and the actuating lever or cam |00 will not be driven as the motor 58 operates. This is the normal condition of the control unit.

In Fig. 3, the finger |56 is set to actuate the lever arm |58 at 7:30 P`. M. As the motor 58 operates to drive the gear train and the clock hands, the dial |54 will be rotated, and at approximately six oclock, the finger |56 will come into contact with the arm-l58 and begin to move the same against the tendency lof spring |64. As the lever arm |58 is rocked in a clockwise direction as viewed in Fig. 11, the finger |63, engaging the end |12 of the cam portion |10 slowly moves the cam element |25 in a counter-clockwise direction as viewed in Fig. 12. As the dial |54 continues to rotate, the cam element is moved to such a position that the surface |10 is moved past the finger |28 of the element |21. The element |21 is not permitted to move, however, at this time because the finger |63 is interposed between the finger |28 and the surface |14 of the cam element |25. At exactly 7:30, the following extremity of the finger |56 will desert the arm |58, and the arm |58 will `thereupon drop to the position of Figs. 3, 11, and l2, under the influence of the spring finger |63 is removed from between the finger |28 and the cam element |25. Thus the spring |32 will be permitted to urge the finger |28 into Contact with the surface |14 of the cam element |25, whereby the pins |66 will be projected into two of the spaces |68r between the spokes |69 of the gear |22.

The gear ratio between the motor 58 and the shaft |23 is such that said shaft |23 makes onehalf revolution in one minute. v As the shaft |23 r |64, whereby the rotates, carrying with it the shaft |24, the actu direction about its pivot 10 until it reaches the position at which the actuator |00 leaves its engagement with the shoe 90. Of course, as the plate 69 is thus moved, the ear I3 drives the pin and arm ||0 to oscillate the rock shaft |06 to 'shift the arm |01 and indicator |08 with respect to the scale |08.

As the shaft |24 rotates, the cam element |25 is carried with it; and as said cam element nears the end of one-half revolution, the cam surface |1| thereof rides under the finger |63, whereby the trigger |62 is rocked about its axis |5I. Al most concurrently, the cam surface 11| rides under the finger |28 of the element |21 whereby, as rotation of the cam element |25 continues, thc element |21 and the clutch |26 are slowly backed away; whereby the pins |65 are withdrawn from their engagement between the spokes |60 of the |68. The parts are so correlated that, at the instant when the finger |63 drops off the end |13 of the cam surface |1|, withdrawal of the 75 ringer |63 dro'ps oli the end |12 pins |66 is complete, and the parts come to rest in the positions illustrated in Figs. i2, 14, and 16 where they remain until the lever arm |58 is actuated by the finger |51, or until said arm is manually actuated.

Similarly, the iinger |51 is shown, in Fig. 3, in a position to actuate the lever arm |58 at approximately 5:50 A. M. Shortly after 4:00 A. M., said iinger |51 will come into contact with the arm |58 and begin to move the same, whereby the finger |63 is caused to cooperate with the end |13 of the cam portion |1| to move the cam element |25. When, at 5:50 A. M., the lever arm |58 drops the following end of the finger |56, the spring |32 will force the pins |66 into engagement between spokes of the gear |22, whereby the shaft |24 and cam |25 will, be driven synchronously with said gear 22.

As the shaft |24 is rotated, the actuator |00 is moved into contact with the'shoe 95, and continued movement of the actuator will force said shoe 95 into the position illustrated in Fig. 5, thus shifting the contact elements 15 and 18 to positions wherein they will be contacted by the fingers 22 and 23 at a temperature substantially correspondingI to that indicated by the indicator 98 on the scale '99.-

As the actuator |00 approaches the position illustrated in Fig. 5,-the fingers |63and |28 ride up on the cam surface |10 whereby, just as the of said cam portion |10, withdrawal of the pins |66 from their engagement between spokes of the gear |22 will be completed, and rotation of the shaft |24 and its connected elements will stop.

.For setting the clock, there is provided a thumb Wheel |15 with which is rigid a pinion |16 meshing with the gear |39. It will be obvious that, as the thumb wheel |15 is pperated, only that portion of the gear train which is separated from the motor 58 by the spring washer |36 will be driven, slip taking place between the gear |35 and the pinion |31. v

The housing 59 is held in place on the base 20 in the manner illustrated inFig. 4. Adjacent its upper end, said base is formed with a notch |11 adapted to receive the latch end |18 of a spring nger ,i 19, a button |80 being provided for depressing said spring iinger.

Preferably, the gear trains and clutch mecha-4 nism are enclosed within housings |8| and |82,

'the housing |8| being formed with a notch |83 permitting the projection ofthe thumb wheel i 15.

i claim as my invention:V

1. A device ofthe class described comprising a von said piece, the pieces of heat insulating material reducing the conduction of heatY through the metal base fromthe clock to the thermostat and 'a housing mountedl on said base and enclosing said motor and said thermostatic element, said housing being formed with perforations only in its top' and bottom surfaces.

2. In combination, a bas, a portion of said base being formed of electrical insulatingmaterialfa pair of terminals on said base for relatively permanent connection to a source ofl electrical energy, a pair of spaced contacts on the insulating por tion of said base permanently connected to said terminals, a pair of guideways on the insulating portion of said base, a frame having guides cooperable with said guideways, a motor carried by said frame, a block of electrical insulating material carried by said frame, and a pair of con- 5 tacts carried by said block, and permanently connected to the terminals of said motor, whereby, when said frame guides are slid into position with respect to said' base guideways, said block contacts will cooperate with said base contacts to establish electrical connection between said base terminals and said motor terminals.

l 3. In combination, a base provided with a pair of parallel rails of insulating material formed with facing grooves, a plurality of electrical contacts mounted on said base and insulated from each other, said contacts being relatively permanently connected to a source of electrical energy,

,and a unit having guides slidably receivable in `perature-responsive unit, and a plurality of contacts permanently connected to the windings of said motor, a plurality of contacts on said base relatively permanently connected to a source of electrical energy and positioned to be engaged by said time-control-unit contacts when said timecontrol unit is in position on said base, and cooperating means on said base and on said timecontrol unit automatically eiective, when said time-control unit is associated with said base, to -vary periodically the relative posmons of said thermostatic element and its 5. In combination, abase, an element pivoted on said base, a rock shaft' mounted on said base and carrying an arm adjacent each end, and interengaging means on the free end of said element and on one of said armsy providing a driving connection between said rock shaftrandsaid element, the other of said arms projecting through a suitably formed slot in said base.

6. In a thermostat, a base, a thermo-responsive member suitably carried on said base, a plate pivoted on saidl base and carrying, adjacent its free end, a contact adapted to be contacted, at times, by said thermo-responsive member, a rock shaft mounted on said base, a graduated scale carried by said base, an arm on said rock shaft and cooperating with said scale, a second arm on said rock shaft, and interengaging means on said plate and on said second arm providing ar driving connection between said rock shaft and said plate, whereby shifting of said first arm with respect to said scale results in shifting of said contact with respect to said thermo-responsive member.

7. An electric clock thermostat, comprising, in combination, `a base including a pair of electric terminals, switching means carried by said base, .thermostatic means in control of said switchingv means,f timing means associated with said associated contact. 45

and including an electric motor and a pair of motor terminals, and connecting means for removably mechanically and electrically connecting said timing means and its terminals to the base and its terminals.

8. An electric clock thermostat comprising, in combination, a base including a pair of electrical terminals, a switch carried by said base, a thermostatic element for operating said switch, timing means for varying the temperature at which the thermostatic element operates said switch, said timing means including an electric motor and a pair of motor terminals, and means loosely supporting said timing means upon said base with the base terminals and motor terminals in engagement.

9. An electric clock thermostat, comprising, in combination, a base including a block of heat and electrical insulating material, a pair of terminals carried by said block and relatively permanently connected to a source of electrical energy, timing means including an electric motor and a pair of motor terminals, means loosely supporting the timing means on said block with the motor terminals in contact with the block terminals.l thermostatic switching means carried by said base, and operative connections between ksaicl timing means and thermostatic switching means.

10. An electric clock thermostat, comprising, in combination, a base including a block of heat and electrical insulating material, a pair of terminals carried by said block and relatively permanently connected to a source of electrical energy, timing means including an electric motor and a pair of motor terminals, connecting means loosely and removably securing said timing means to said block with the motor terminals in contact with the blocl-r terminals, a switch carried by said base, a thermostatic element for operating said switch, and operative connections between said timing means and said thermostatic means through which'the timing means is operative to change the temperature at which `the thermostatic element operates said switch.

1l. An electric clock thermostat, comprising, in combination, an elongated base including a block. of heat and electrical insulating material mounted near the upper end thereof, a thermostatic element mounted near the lower end of said base, a switch controlled thereby, timing means including an electric motor adapted to be associated with said switch for changing the action of the thermostatic element thereon, a

pair of motor terminals carried by said timing means, a. pair of terminals carried by said block and relatively permanently connected tol a source of electrical power, connections enabling removable mounting of the timing means on the block with the motor terminals in contact with the block terminals, and a cover adapted to surround said thermostatic element and timing means and being provided with Ventilating openings in the top and bottom.

12. In combination, a base, a portion of said base being formed of electrical insulating material, a pair of facing guideways formed in said insulating material, a pair of terminals on said base for relatively permanent connection to a source of electrical energy, a pair of spaced contacts located on the insulating portion of said baseadjacent one of said guideways and spaced longitudinally thereof and permanently connected to said terminals, a frame having guides cooperable with said guideways, a motor carried by said frame, a block of electrical insulating` material carried by said frame, and a pair of contacts carried by said block, and permanently connected to the terminals of said motor, whereby, when said frame guides are slid into position with respect to said base guideways, said block contacts will cooperate with said base contacts to establish electrical connections between said base terminals and said motor terminals. y

13. In combination, a base, a portion of said base being formed of electrical insulating material, a pair of facing guideways formed in said insulating material, a pair of terminals on said base for relatively permanent connection to a 35 source of electrical energy, a pair of spaced contacts located on the insulating portion of said base adjacent one of said guideways and spaced longitudinally thereof and permanently connected to said terminals, a frame having guides cooperable with said guideways, a motor carried by said frame, a block of electrical insulating material, carried by said frame, anda pair of contacts carried by said block, spaced longitudinally of one of said guides, and permanently connected to the terminals of said motor, whereby, when said frame guides are slid into position with resp'ect to said base guideways, one of said block contacts is moved across one oisaid base contacts/and into engagement with the other of said base contacts, while the other of said block contacts is moved into engagement with said first-mentioned one of said base contacts. 

